Duncan, J. C. (1920). “Bright nebulae and star clusters in Sagittarius and Scutum photographed with the 60-inch reflector”. The Astrophysical Journal51: 4. Bibcode: 1920ApJ....51....4D. doi:10.1086/142519.
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Duncan, J. C. (1920). “Bright nebulae and star clusters in Sagittarius and Scutum photographed with the 60-inch reflector”. The Astrophysical Journal51: 4. Bibcode: 1920ApJ....51....4D. doi:10.1086/142519.
Flagey, Nicholas (January 2009). “The Eagle Nebula Unveiled by the Spitzer/MIPSGAL Survey”. Bulletin of the American Astronomical Society41 (1): 37. Bibcode: 2009AAS...21332401F.
